1. Field of the Invention
The present invention relates to the technical field of image processing and, more particularly, to a temporal vector processing device and method for reducing a film judder on motion estimation.
2. Description of Related Art
An advanced television signal processing typically includes motion estimation and compensation applied to a frame rate conversion to thereby increase the effective frame rate of a temporal signal and further reduce motion judder or blur. The motion judder generally occurs in a video signal of a film or in display on a large screen. The motion blur typically originates in an LCD display technique. The article “True-Motion estimation with 3-D recursive search block matching”, IEEE transactions on circuits and systems for video technology, Vol. 3, No. 5, October 1993, has been proposed to select the spatial and temporal candidate vectors and perform a spatially and temporally recursive processing on the selected candidate vectors to thereby speed up the convergence to the true motion vector under fewer operations or lower computational amount. How a preferred candidate vector is selected can determine the accuracy of the final motion vector. Typically, a spatial consistency and a temporal correlation are considered on selecting a candidate vector. The spatial consistency is based on an assumption that an object is a rigid body and has a certain space, and the temporal correlation is based on an assumption that the object presents a uniform motion. When a correct motion vector occurs in the candidate vectors, a motion vector can gain a higher opportunity on converging to the correct motion vector, and instead an error candidate vector can interfere a motion estimation to increase the opportunity of obtaining an error motion vector. FIG. 1 is a schematic diagram of typical spatial and temporal motion vectors. As shown in FIG. 1, a motion estimation and a motion compensation are performed on a pixel (i, j), where the spatial candidate vectors SMV0, SMV1, SMV2 and the temporal candidate vector TMV are used to achieve the purpose of speeding up a convergence to the true motion vector.
FIG. 2 is a schematic graph of a temporal motion vector generation in the prior art. If a motion estimation is performed between the time Tn−1 and Tn, and the position of the motion vector MVn−1 corresponds to the time Tn−1, a pixel P(i) at Tn−1 has a motion vector MVn−1(i) that can have a future movement to the point corresponding to a pixel P(i+MVn−1) at Tn. However, the motion vector MVn−1(i) of the pixel P(i) is stored in the storage location of the pixel P(i).
When the motion vector MVn between Tn and Tn+1 is calculated, the temporal motion vector of the pixel (i) (solid block) at Tn is related with a pixel (i−3) at Tn−1. Namely, when an object is being moved at a constant speed, the temporal motion vector of the pixel (i) at Tn is the speed of the pixel (i) at Tn. That is, the temporal motion vector of the pixel (i) at Tn is obtained by adding the point of the pixel P(i−3) at Tn−1 and the vector MVn−1 of the pixel P(i−3) and moving the added to the position of the pixel P(i) at Tn. In this case, the vector MVn−1 indicates the temporal motion vector of the pixel (i) at Tn. If a motion vector range locates from −5 to +5, the pixels from the position of a pixel P(i−5) to the position of a pixel P(i+5) and the motion vector MVn−1 at Tn−1 possibly move to the pixel P(i) at Tn. When the object is covered, two or more motion vectors corresponding to the pixel P(i) at passing through Tn may be found in the range. When the object is uncovered, no motion vector corresponding to the pixel P(i) at passing through Tn may be seen in the range. In the prior art, the motion vector MVn−1(i) of the pixel P(i) at Tn−1 is stored in the storage location of the pixel (i), so that the motion vector MVn−1(i) is outputted at Tn, and accordingly the range is searched to thus generate the temporal motion vector. When the motion vector range increases, the computation of searching the range relatively increases, so that the computational amount is too large to meet the practical requirement.
Therefore, it is desirable to provide an improved processing device and method to mitigate and/or obviate the aforementioned problems.